CPR chest compression machine stopping to detect patient recovery

ABSTRACT

Embodiments of the present concept are directed to CPR chest compression machines that include a sensor to detect a parameter about a patient, such as an indication of patient recovery, and include a processor that determines whether to cease series of successive compressions on the patient in response to the detected parameter.

CROSS REFERENCE TO RELATED PATENT APPLICATIONS

This application is a continuation of U.S. application Ser. No.13/181,384, filed on Jul. 12, 2011, now U.S. Pat. No. 9,198,826, andIssued on Dec. 1, 2015, which claims the benefit of the followingProvisional Patent Applications: U.S. Provisional Patent ApplicationSer. No. 61/363,996, filed on Jul. 13, 2010; U.S. Provisional PatentApplication Ser. No. 61/444,091, filed on Feb. 17, 2011; U.S.Provisional Patent Application Ser. No. 61/444,888, filed on Feb. 21,2011; U.S. Provisional Patent Application Ser. No. 61/495,176, filed onJun. 9, 2011.

The disclosure of each application is hereby incorporated by referencefor all purposes.

FIELD

This invention generally relates to CPR chest compression machines.

BACKGROUND

In certain types of medical emergencies, Cardio-Pulmonary Resuscitation(“CPR”) needs to be delivered to a patient. CPR includes repeatedlycompressing the chest of the patient, to cause their blood to circulatesome. CPR also includes delivering rescue breaths to the patient. Anumber of people are trained in CPR, just in case, even though they arenot trained in the medical professions.

The chest compressions are intended to prevent damage to organs like thebrain. In some instances, the chest compressions merely maintain thepatient, until a more definite therapy is made available, such asdefibrillation. Defibrillation is an electrical shock deliberatelydelivered to a person, in the hope of correcting their heart rhythm.

A problem is that CPR is sometimes ineffective for preventing damage tothe patient. That can happen whether or not the rescuer who performs theCPR is part of the medical profession. The most frequent example of suchineffectiveness is compressions that are not deep enough, or notfrequent enough. Even the best trained rescuers can become fatiguedafter delivering CPR, with the compressions deteriorating in quality.And that is without even accounting for the emotions of the moment,which might impact a lay rescuer.

The risk of ineffective chest compressions has been addressed in part bydefibrillator manufacturers. Some defibrillators nowadays issue verbaland visual prompts and other instructions as to how CPR is to beperformed. These are often according to the guidelines of medicalexperts, such as the American Heart Association. These prompts and otherinstructions can help the rescuer focus better, even if the lattercannot remember their training.

The risk of ineffective chest compressions has been additionallyaddressed with CPR feedback devices. These devices actually detect thedepth and frequency of compressions that the rescuer is performing, andgive feedback that is specifically attuned to what the rescuer is doing.This feedback can be in accordance with the how well the rescuer ismeeting the above mentioned guidelines, especially in achieving theindicated depth of compressions.

Reaching the appropriate depth is difficult. The recommended depth is arange. If the actual depth is less than the range, not enough blood ismoved within the patient. If the depth exceeds the range, the patient'sribs may break. And, even for experienced rescuers, it is sometimes hardto discern the appropriate depth. Reaching the appropriate depth is evenmore difficult if the patient is on a flexible mattress that partlyrecedes, as the rescuer is pushing from the top. And CPR compressionsare even more challenging, if the rescuer has to deliver them in amoving ambulance.

The risk of ineffective chest compressions has been moreover addressedwith CPR chest compression machines. Such machines have been known by anumber of names, such as mechanical CPR devices, cardiac compressors,external chest compression machines, and so on.

CPR chest compression machines repeatedly compress and release the chestof the patient. Such machines can be programmed so that they willcompress and release at the recommended rate, and always reach aspecific depth within the recommended range.

Although CPR chest compression machines can be used in conjunction withexternal defibrillators, not all ailments for which a CPR chestcompression machine is used require defibrillation. Hence, manytreatment protocols instruct the use of CPR without the need toelectrically shock the patient's heart.

Although it is generally good to perform CPR chest compressions, it issometimes difficult to know when to stop compressions. A CPR machine, oreven a rescuer may not notice that a patient has regained spontaneouscirculation and compressions may continue to be given even though thepatient's heart is beating. Occasionally the patient may regainconsciousness during compressions. This may cause the patient pain anddiscomfort, as well as potentially scaring them and causing additionalemotional or physical trauma.

Even when the CPR chest compression machine helps the patient return tospontaneous circulation while they are still comatose, it is stilldesirable to stop the CPR chest compression machine promptly because 1)its compressions can interfere with the normal filling of heart chambersbetween spontaneous heart contractions, thus decreasing the cardiacoutput caused by those spontaneous heart contractions, and 2) itscompressions can, under certain circumstances, increase the probabilitythat the heart will return to ventricular fibrillation.

BRIEF SUMMARY

The present description gives instances of medical devices, systems, andmethods, the use of which may help overcome problems and limitations ofthe prior art.

In particular, embodiments of the present concept are directed to CPRchest compression machines that include a sensor to detect a parameterabout a patient, such as an indication of patient recovery, and includea processor that determines whether to cease series of successivecompressions on the patient in response to the detected parameter.

In some embodiments, a machine for performing Cardio-PulmonaryResuscitation (“CPR”) chest compressions includes a mechanism fordelivering successive compressions to a chest of a patient, a driver fordriving the mechanism, and a processor for controlling the driver todrive the mechanism to deliver successive chest compressions or stop thedelivery of successive chest compressions. In these embodiments, the CPRchest compression machine also includes a sensor adapted to detect aparameter about the patient and output a sensor signal indicative of avalue of the parameter, and includes a generation means forautomatically generating a constituent value. Here, the processor isconfigured to stop delivery of a series of successive compressions for astatic value of the parameter to be detected by the sensor, to determinefrom the constituent value whether a restart condition is met, and toimplement another series of successive chest compressions if the restartcondition is met.

In other embodiments, a method for a Cardio-Pulmonary Resuscitation(“CPR”) compression machine having a mechanism for delivering successivecompressions to a chest of a patient is disclosed. This method includescontrolling the mechanism to deliver and end delivery of a first seriesof successive compressions to the chest of the patient, and detecting astatic value of a first parameter about the patient while the patient isnot receiving chest compressions. A first sensor signal indicative ofthe static value is outputted, and a constituent value is automaticallygenerated. It is then determined from the constituent value whether arestart condition has been met. If the restart condition is met, themechanism is controlled to deliver a second series of successivecompressions.

An advantage over the prior art is that patient recovery can be detectedduring automatic series of successive chest compressions and thecompressions can be paused or ended so that the patient is not put atrisk for feeling pain or discomfort from the chest compressions.

These and other features and advantages of this description will becomemore readily apparent from the following Detailed Description, whichproceeds with reference to the drawings, in which:

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram of an abstracted compression structure of a CPRchest compression machine in the prior art.

FIG. 2 is a diagram of a sample compression structure of a CPR chestcompression machine in the prior art.

FIG. 3 is a diagram of a controller for a compression structure of a CPRchest compression machine according to embodiments.

FIG. 4 is a diagram of a CPR chest compression machine according toembodiments.

FIGS. 5A, 5B, 5C, and 5D are timeline diagrams illustrating sampledetection pauses for detecting parameters about a patient duringsuccessive chest compressions according to embodiments.

FIGS. 6A, 6B, and 6C are timeline diagrams illustrating dynamic sampledetection periods for detecting parameters about a patient duringsuccessive chest compressions according to embodiments.

FIG. 7 is a flowchart for illustrating methods according to embodiments.

FIG. 8 is another flowchart for illustrating methods according toembodiments.

DETAILED DESCRIPTION

As has been mentioned, the present description is about medical devices,systems, and methods for stopping a CPR chest compression machine todetect patient recovery.

Embodiments are now described in more detail.

FIG. 1 is a diagram of an abstracted compression structure 140 of a CPRchest compression machine in the prior art. A patient 182 is placedwithin compression structure 140. A driver 141 is then controlled todrive the compression structure 140 to repeatedly compresses andreleases their chest. These compressions and releases are designated byarrow 148, regardless of how effectuated.

Compression structure 140 is shown as reaching around the chest ofpatient 182. This alleviates the above-mentioned problem of the patientbeing on a flexible mattress, which causes ineffective CPR. Indeed,compressions 148 are with respect to compression structure 140, not themattress. But structure 140 typically does not cover, for example, thehead of patient 182.

Compression structure 140 is abstracted, in that it may be implementedin any number of ways. In some embodiments, a belt squeezes and releasesthe patient's chest. A piston embodiment is now described.

FIG. 2 is a diagram of a sample compression structure 240 of a CPR chestcompression machine in the prior art. Structure 240 includes a member242. A backboard 242 is attached to member 242. Patient 282 is placed onbackboard 244. A piston 246 is attached to member 242. A driver 241 iscontrolled to drive the piston 246 automatically up and down to delivercompressions and releases 248.

FIG. 3 is a diagram of a controller 310 according to embodiments.Controller 310 may be coupled with a User Interface 314, for receivinguser instructions, and for outputting data.

Controller 310 includes a processor 320. Processor 320 can beimplemented in any number of ways, such as with a microprocessor,Application Specific Integration Circuits, programmable logic circuits,general processors, etc. While a specific use is described for processor320, it will be understood that processor 320 can either be standalonefor this specific use, or also perform other acts.

Controller 310 additionally includes a memory 330 coupled with processor320. Memory 330 can be implemented by one or more memory chips. Memory330 stores instructions 332 for execution by processor 320. While aspecific use is described for memory 330, it will be understood thatmemory 330 can hold additional data.

Controller 310 is intended to control a driver 341 which drives,according to arrow 318, compressions 348 of a compression structure 340of a CPR chest compression machine. Compressions 348 are delivered to apatient 382, who is in the compression structure 340. In addition,controller 310 receives data about compression structure 340, forexample a time profile of compressions, according to arrow 319.

Controller 310 may be implemented together with the driver 341 andcompression structure 340, in a single CPR chest compression machine. Insuch embodiments, arrow 318 is internal to such a CPR chest compressionmachine. Alternately, controller 310 may be hosted by a differentmachine, which communicates with the driver 341 of a CPR chestcompression machine that uses compression structure 340. Suchcommunication can be wired or wireless. The different machine can be anykind of device, such as a medical device. One such example is describedin commonly assigned U.S. Pat. No. 7,308,304, titled “COOPERATINGDEFIBRILLATORS AND EXTERNAL CHEST COMPRESSION MACHINES”, the disclosureof which is incorporated by reference. Similarly, User Interface 314 maybe implemented on the CPR chest compression machine, or on a hostdevice.

In some embodiments, a group 350 of patient parameter measuring modulesis also provided. Group 350 is shown as including modules 351, 352, 353,. . . , for measuring parameters of patient 382. These parameters caninclude Arterial Systolic Blood Pressure (ABSP), blood oxygen saturation(SpO2), ventilation measured as End-Tidal CO2 (ETCO2), temperature,detection of pulse, etc. In addition, these parameters can include whatis detected by defibrillator electrodes that may be attached to patient382, such as ECG and impedance. Modules 351, 352, 353, . . . can beimplemented either on a separate standalone monitor device, or on thesame CPR chest compression machine as compression structure 340. Modules351, 352, 353, . . . can be implemented either on the same device ascontroller 310 or not, and so on. Many permutations are possible.

Upon sensing patient 382, modules 351, 352, 353 output values 361, 362,363 respectively, of the parameters they measure. Values 361, 362, 363are received by controller 310.

Controller 310 further optionally aggregates resuscitation data, fortransmission to a post processing module 390. There are a number ofpossibilities for the resuscitation data, such as event data, time data,patient data, CPR delivery date, and so on. The resuscitation data caninclude what is learned via arrow 319, values 361, 362, 363, etc.Transmission can be performed in many ways, as will be known to a personskilled in the art. In addition, controller 310 can transmit status dataof the CPR chest compression machine that includes compression structure340.

FIG. 4 is a diagram of another CPR chest compression machine 400according to embodiments. The CPR chest compression machine 400 includesa mechanism 440 for delivering successive compressions 448 to a chest ofa patient 482 and a driver 441 for driving the mechanism. A first sensor450 in the CPR chest compression machine 400 is adapted to detect afirst parameter about the patient 482 and output a first sensor signalindicative of a value 460 of the first parameter. It will be appreciatedthat value 460 can be called a dynamic value if the first parameter isdetected while compressions are being delivered to the chest, and astatic value if the first parameter is detected while compressions arenot being delivered. Correspondingly, detection during compressions canbe called dynamic detection, while detection during a pause can becalled static detection.

In addition, a generation means 452 is also included, and is configuredto automatically generate a constituent value 462. As will beappreciated by the remainder of this document, any number of elementscan be considered to be the generation means, with the correspondingoutput being the constituent value 462. The final choice of thegeneration means will depend on the desired embodiment.

The CPR chest compression machine 400 also includes a processor 420 thatis operable for controlling the driver 441 to drive the mechanism 440 todeliver the successive compressions 448. Specifically, the processor 420controls the driver 441 to drive the mechanism 440 to deliver a firstseries of successive compressions 448, then controls the driver to drivethe mechanism to stop delivering the first series of successivecompressions for a static value 460 of the first parameter to bedetected by the first sensor 450 while the patient 482 is not receivingchest compressions. The processor 420 determines from the constituentvalue 462 whether a restart condition is met, and then controls thedriver 441 to drive the mechanism 440 to start delivering a secondseries of successive compressions 448 if the restart condition is met.The processor does not control the driver 441 to drive the mechanism 440to deliver additional successive compressions 448 when the restartcondition is not met.

The mechanism 440 that delivers the successive compressions 448 may beimplemented in any number of ways, as was described for FIG. 1, fordelivering CPR chest compressions to a patient 482 according to CPRprotocols to a patient 482.

The restart condition can be dependent on various conditions ormeasurements in different embodiments, which further define what is alsothe corresponding generation means. In some embodiments, the generationmeans 452 is one of a clock or a counter where the constituent value 462is time. Here, the restart condition is met when a first time intervalhas elapsed after the first series of successive compressions hasstopped. In some embodiments, the restart condition is met also when adata measurement corresponding to the static value 460 has beencompleted, in addition to what is determined from the constituent value.

In yet other embodiments, the generation means 452 is coupled to receivethe first sensor signal from the first sensor 450. Here, the constituentvalue 462 is a digital rendering of the static value 460 that has beendecoded from the first sensor signal. The restart condition may be metwhen the constituent value 462 is first generated. Alternatively, therestart condition may be met when a computation from the constituentvalue 462 is indicated as having been completed.

In another example embodiment, the restart condition is met if adetermination has been made automatically from the static value thatcontinuing compressions is merited. The first sensor 450 may be furtheradapted to determine a dynamic value 460 of the first parameter whilethe patient is receiving chest compressions. Here, the determination ofwhether the restart condition is met may be based on a comparison of thestatic value and the dynamic value.

The length of the second or other series of successive compressions maybe dependent on the values 460 from the detected first parameter.Similarly, the length of time for the detection of the static value maybe variable based on previous measurements. For example, if a firstmeasurement of the static value 460 of the first parameter indicatesthat a patient is getting closer to recovery, the length of time for thenext series of compressions may be shortened and a different constituentvalue may be used to detect patient recovery during a longer pause inthe compressions.

The first series of successive compressions 448 may include ventilationpauses for the patient 482 to receive the ventilations. The patient 482may receive ventilation from a ventilation machine 490 coupled to theCPR compression machine 400, or from a human provider. In theseembodiments, the first series of compressions 448 may be stopped at thebeginning of one of the ventilation pauses.

The CPR chest compression machine 400 may also include a user interface414 in some embodiments. The user interface 414 may be adapted to outputan alert message to a user if the restart condition is not met. In otherembodiments, the processor 420 causes an alert message to becommunicated to a device other than the machine 400 if the restartcondition is not met.

The processor 420 may be further adapted to determine whether a stoppingcriterion is met. Here, the stopping criterion may be determined fromthe static value 460. When the stopping criterion is met, the processor420 controls the driver 441 to drive the mechanism 440 to stop deliveryof the second series of successive compressions 448 for the firstparameter to be detected again by the first sensor 450 while the patient482 is not receiving chest compressions. The processor 420 may thencontrol the driver 441 to drive the mechanism 440 to start delivering athird series of successive compressions 448 when it is merited.

Alternatively, the second series of successive compressions 448 may bestopped at a second time determined from the static value 460. Thisdetermination may be dependent on whether the detected static value 460exceeds a threshold. The first parameter detected about the patient 482by the first sensor 450, from which the static value is based, mayinclude many different types of data, such as one or more of thefollowing example parameters: 1) Arterial systolic blood pressure, wherethe threshold may be, for example, about 80 millimeters of mercury; 2)Blood oxygen saturation, where the threshold may be, for example, about90 percent; 3) End tidal carbon dioxide, where the threshold may be, forexample, about 30 millimeters of mercury; 4) Blood velocity, where thethreshold may be, for example, zero ml/s; and/or 5) A patient's ECG,where the threshold may be an ECG threshold criterion that is met. TheECG threshold criterion can be implemented in a number of ways. Oneexample is a QRS rate of above about 60 beats/min. Another example is aQRS acceleration rate of 2 beats/minute every second. Another examplemay be about an aspect of the morphology of measured QRS complexes.Examples of possible morphologies include a QRS width of less than about120 msec.

In embodiments where the CPR chest compression machine 400 includes auser interface 414, the user interface may be adapted to output an alertmessage to a user when the first parameter exceeds the threshold.

FIGS. 5A, 5B, 5C, and 5D are timeline diagrams illustrating sampledetection pauses for detecting parameters about a patient duringsuccessive chest compressions according to embodiments.

Referring to FIG. 5A, a first series of compressions 502 are initiatedat time T0. Detection of the first parameter 510 during this firstseries of compressions 502 results in dynamic values. At T1, theprocessor controls the driver to stop the mechanism from delivering thefirst series of chest compressions 504 so that a static value 512 of thefirst parameter 510 can be detected. As discussed above, the delivery ofsuccessive chest compressions can interfere with some parametermeasurements due to the manipulation of the patient's chest. By stoppingor pausing the first series of successive chest compressions moreprecise values about the first parameter may be detected that can beassociated with patient recovery. Values thus obtained are called staticvalues. In this illustrated example, the static value 512 based on themeasured first parameter indicates that the patient is experiencing aReturn Of Spontaneous Circulation (ROSC) 508. Hence, a restart conditionis not met since the patient may be recovering consciousness, andadditional series of successive compressions are not delivered. However,the first parameter 510 continues to be monitored in case the patientloses ROSC and required additional chest compressions.

Referring to FIG. 5B, a first series of chest compressions 522 is againinitiated at time T0 and a first parameter is detected about the patient530. The first parameter includes dynamic values 534 during the firstseries of compressions 522, but returns a static value 532 when thefirst series of compressions is paused 524 at time T1 for the staticmeasurement of the first parameter. Here, the processor determines froma constituent value that a restart condition was met, and a secondseries of chest compressions 526 is initiated at time T2. This may bebecause the static value of the detected first parameter does not meet apredefined threshold. During this second series of chest compressions526, the detection of the first parameter returns to dynamic values 534.

Referring to FIG. 5C, a first series of chest compressions 542 is againinitiated at time T0 and a first parameter 550 is detected about thepatient. The first parameter includes dynamic values 554 during thefirst series of compressions 542, but returns a static value 552 whenthe first series of compressions is paused 544 at time T1 for the staticmeasurement of the first parameter. Here, the processor determines froma constituent value that a restart condition was met, and a secondseries of chest compressions 546 is initiated at time T2. During thissecond series of chest compressions 546, the detection of the firstparameter returns to dynamic values 554. Here, however, the secondseries of chest compressions 546 does not last as long as the firstseries of chest compressions 542. This may be because the dynamic values554 of the first parameter indicate that the patient may be recoveringand a static measurement is requested to confirm recovery, or becausethe measured static value 552 detected during the first detection pause544 may have indicated that the patient was getting close to recovery.

In either case, a second detection pause 548 is initiated at time T3 anda static value 552 of the first parameter 550 is again measured. Here,the generation means may output a different constituent value since thepatient may be getting close to recovery and additional detection timefor the static value may be required. This results in the seconddetection 448 pause being longer than the first detection pause 544. Inthis instance, it is detected that the patient is showing signs ofrecovery, such as a return of spontaneous circulation 549, from thedetected static value and additional chest compressions are notdelivered.

Referring to FIG. 5D, a first series of compressions 562, firstdetection pause 564, and second series of compressions 568 may besimilar to those illustrated in FIG. 5C. Likewise, the detection of thefirst parameter 570 may again include portions of dynamic valuemeasurement 574 during the compressions, and static value measurement572 during the detection pauses. In this instance, however, the staticvalue measured from the detected first parameter 570 during the seconddetection pause 568 does not indicate that the patient has recovered.This may be because the static value of the detected first parameterdoes not meet a predefined threshold. Hence, a restart condition is metand a third series of compressions 570 is initiated at time T4.

With reference back to FIG. 4, in some embodiments, the CPR chestcompression machine 400 includes a second sensor 455 adapted to detect adynamic value 465 of a second parameter different from the firstparameter, the dynamic value detected about the patient 482 while thepatient is receiving the first series of chest compressions 448. Here,the first series of chest compressions 448 may be stopped at a firsttime determined from the dynamic value 465. The dynamic value 465 may bereceived automatically from the second sensor 455 or may be entered viathe user interface 414 by a human rescuer.

Again, the second series of successive compressions 448 may be stoppedat a second time determined from the dynamic value 465. Thisdetermination may be dependent on whether the detected dynamic value 465exceeds a threshold.

Similar to the first parameter detected about the patient 482, thesecond parameter detected from the second sensor 455, from which thedynamic value 465 is detected, may include many different types of data,such as one or more of the following example parameters: 1) Arterialsystolic blood pressure, where the threshold may be, for example, about80 millimeters of mercury; 2) Blood oxygen saturation, where thethreshold may be, for example, about 90 percent; 3) End tidal carbondioxide, where the threshold may be, for example, about 30 millimetersof mercury; 4) Blood velocity, where the threshold may be, for example,zero ml/s; and/or 5) A patient's ECG, where the threshold may be an ECGthreshold criterion that is met. Examples of ECG threshold criteria aregiven above.

In embodiments where the CPR chest compression machine 400 includes auser interface 414, the user interface may be adapted to output an alertmessage to a user when the second parameter exceeds the threshold.

FIGS. 6A, 6B, and 6C are timeline diagrams illustrating dynamic sampledetection periods for detecting parameters about a patient duringsuccessive chest compressions according to embodiments. In someembodiments, the values of these parameters can ultimately helpdetermine whether Return Of Spontaneous Circulation (“ROSC”) hasoccurred in the patient. While ROSC is mostly described here, there canbe other detected conditions that would warrant stopping chestcompressions, such as internal trauma, or deteriorating condition, oreven futility of CPR such as irreversible-type death.

Referring to FIG. 6A, a first series of compressions 602 are initiatedat time T0. In this example, both a first parameter 610 and a secondparameter 620 are detected. The first parameter may include detection ofa parameter that has more relevant values when the patient is notreceiving chest compressions, such as blood velocity, and the secondparameter may include detection of a parameter that can be moremeaningful by its value changes at the transition time when chestcompressions are stopped, such as blood velocity, blood pressure, bloodoxygen saturation, end tidal carbon dioxide. Where the decision torestart or prompt from stopping the next series can be based on trendingof static and/or dynamic values of parameters. If trending is employed,then suitable thresholds can be set accordingly, such as thresholds ofrates, duration, and so on.

Detection of the first parameter 610 and second parameter 620 duringthis first series of compressions 602 result in respective dynamicvalues 614, 622. The dynamic values 622 of the second parameter 622 maybe more closely monitored during chest compressions for signs of patientrecovery. At T1, the processor controls the driver to stop the mechanismfrom delivering the first series of chest compressions 604 so thatstatic values 612, 624 of the first and second parameter 610, 620 can bedetected. Here, the focus of the parameter detection values may shift tothe static value 612 related to the detected first parameter. Thestopping criteria may be a suitable combination of the static anddynamic values.

In this illustrated example, the static value 612 based on the measuredfirst parameter indicates that the patient is experiencing a Return OfSpontaneous Circulation (ROSC) 606. Hence, a restart condition is notmet since the patient may be recovering consciousness, and additionalseries of successive compressions are not delivered. However, the firstand second parameters 610, 620 are still monitored, in case the patientlater loses ROSC and required additional chest compressions.

Referring to FIG. 6B, a first series of compressions 632 are initiatedat time T0. In this example, both a first parameter 640 and a secondparameter 650 are detected. Detection of the first parameter 640 andsecond parameter 650 during this first series of compressions 632 resultin respective dynamic values 644, 652. At T1, the processor controls thedriver to stop the mechanism from delivering the first series of chestcompressions 634 so that static values 642, 654 of the first and secondparameter 640, 650 can be detected.

In this illustrated example, a restart condition is met and a secondseries of chest compressions 636 is initiated at time T2. Here, duringthe second series of chest compressions 636, the dynamic value 652 ofthe detected second parameter 650 indicates that a patient may berecovering and the second series of compressions is stopped at time T3.During this detection stop 638, the first and second parameters 640, 650are monitored to ensure that the patient has recovered. In thisinstance, ROSC in the patient is detected from the static value 642 ofthe first parameter 640 and additional compressions are not delivered tothe patient.

Referring to FIG. 6C, a first series of compressions 662 are initiatedat time T0. In this example, both a first parameter 670 and a secondparameter 680 are detected. Detection of the first parameter 670 andsecond parameter 680 during this first series of compressions 662 resultin respective dynamic values 674, 682. At T1, the processor controls thedriver to stop the mechanism from delivering the first series of chestcompressions 664 so that static values 672, 684 of the first and secondparameter 670, 680 can be detected.

In this illustrated example, a restart condition is met and a secondseries of chest compressions 665 is initiated at time T2. At T3, theprocessor again controls the driver to stop the mechanism fromdelivering the second series of chest compressions 665 so that staticvalues 672, 684 of the first and second parameter 670, 680 can bedetected. A restart condition is again met and a third series of chestcompressions 668 is initiated at time T4. Here, during the third seriesof chest compressions 668, the dynamic value 682 of the detected secondparameter 680 indicates that a patient is experiencing ROSC 669 and thethird series of compressions is stopped at time T5. Although additionalseries of successive chest compressions are not delivered to thepatient, the first and second parameter 670, 680 are continuallymonitored to ensure that the patient remains in recovery.

The functions of this description may be implemented by one or moredevices that include logic circuitry. The device performs functionsand/or methods as are described in this document. The logic circuitrymay include a processor that may be programmable for a general purpose,or dedicated, such as microcontroller, a microprocessor, a DigitalSignal Processor (DSP), etc. For example, the device may be a digitalcomputer like device, such as a general-purpose computer selectivelyactivated or reconfigured by a computer program stored in the computer.Alternately, the device may be implemented by an Application SpecificIntegrated Circuit (ASIC), etc.

Moreover, methods are described below. The methods and algorithmspresented herein are not necessarily inherently associated with anyparticular computer or other apparatus. Rather, various general-purposemachines may be used with programs in accordance with the teachingsherein, or it may prove more convenient to construct more specializedapparatus to perform the required method steps. The required structurefor a variety of these machines will become apparent from thisdescription.

In all cases there should be borne in mind the distinction betweenmethods in this description, and the method of operating a computingmachine. This description relates both to methods in general, and alsoto steps for operating a computer and for processing electrical or otherphysical signals to generate other desired physical signals.

Programs are additionally included in this description, as are methodsof operation of the programs. A program is generally defined as a groupof steps leading to a desired result, due to their nature and theirsequence. A program is usually advantageously implemented as a programfor a computing machine, such as a general-purpose computer, a specialpurpose computer, a microprocessor, etc.

Storage media are additionally included in this description. Such media,individually or in combination with others, have stored thereoninstructions of a program made according to the invention. A storagemedium according to the invention is a computer-readable medium, such asa memory, and is read by the computing machine mentioned above.

Performing the steps or instructions of a program requires physicalmanipulations of physical quantities. Usually, though not necessarily,these quantities may be transferred, combined, compared, and otherwisemanipulated or processed according to the instructions, and they mayalso be stored in a computer-readable medium. These quantities include,for example electrical, magnetic, and electromagnetic signals, and alsostates of matter that can be queried by such signals. It is convenientat times, principally for reasons of common usage, to refer to thesequantities as bits, data bits, samples, values, symbols, characters,images, terms, numbers, or the like. It should be borne in mind,however, that all of these and similar terms are associated with theappropriate physical quantities, and that these terms are merelyconvenient labels applied to these physical quantities, individually orin groups.

This detailed description is presented largely in terms of flowcharts,display images, algorithms, and symbolic representations of operationsof data bits within at least one computer readable medium, such as amemory. Indeed, such descriptions and representations are the type ofconvenient labels used by those skilled in programming and/or the dataprocessing arts to effectively convey the substance of their work toothers skilled in the art. A person skilled in the art of programmingmay use these descriptions to readily generate specific instructions forimplementing a program according to the present invention.

Often, for the sake of convenience only, it is preferred to implementand describe a program as various interconnected distinct softwaremodules or features, individually and collectively also known assoftware. This is not necessary, however, and there may be cases wheremodules are equivalently aggregated into a single program with unclearboundaries. In any event, the software modules or features of thisdescription may be implemented by themselves, or in combination withothers. Even though it is said that the program may be stored in acomputer-readable medium, it should be clear to a person skilled in theart that it need not be a single memory, or even a single machine.Various portions, modules or features of it may reside in separatememories, or even separate machines. The separate machines may beconnected directly, or through a network, such as a local access network(LAN), or a global network, such as the Internet.

It will be appreciated that some of these methods may include softwaresteps that may be performed by different modules of an overall softwarearchitecture. For example, data forwarding in a router may be performedin a data plane, which consults a local routing table. Collection ofperformance data may also be performed in a data plane. The performancedata may be processed in a control plane, which accordingly may updatethe local routing table, in addition to neighboring ones. A personskilled in the art will discern which step is best performed in whichplane.

An economy is achieved in the present document in that a single set offlowcharts is used to describe both programs, and also methods. So,while flowcharts are described in terms of boxes, they can mean bothmethod and programs.

For this description, the methods may be implemented by machineoperations. In other words, embodiments of programs are made such thatthey perform methods of the invention that are described in thisdocument. These may be optionally performed in conjunction with one ormore human operators performing some, but not all of them. As per theabove, the users need not be collocated with each other, but each onlywith a machine that houses a portion of the program. Alternately, someof these machines may operate automatically, without users and/orindependently from each other.

Methods are now described.

FIG. 7 is a flowchart for illustrating methods for a Cardio-PulmonaryResuscitation (“CPR”) compression machine having a mechanism fordelivering successive compressions to a chest of a patient according toembodiments. Although this flowchart illustrates a variety of operationsin a particular order, these operations may be carried out in differentorders to achieve similar results in other method embodiments. Themethod shown in this illustrated flow chart may be practiced, forexample, by the CPR chest compression machine 400 shown in FIG. 4.

According to an operation 710, a mechanism is controlled to deliver afirst series of successive compressions to the chest of the patient.According to another operation 720, the mechanism is then controlled toend delivery of the first series of successive compressions. In anotheroperation 730, a static value of a first parameter about the patient isdetected while the patient is not receiving chest compressions. Here, afirst sensor signal indicative of the static value is outputted.

According to another operation 740, a constituent value is automaticallygenerated, and from the constituent value it is determined in operation750 whether a restart condition has been met. If the start condition ismet, the mechanism is controlled to deliver a second series ofsuccessive compressions in operation 760. If the start condition is notmet, successive compressions are not restarted and an optional operation770 may cause an alert message to be outputted. This alert message maybe outputted to a user interface of the machine if the restart conditionis not met, or to a device other than the machine if the restartcondition is not met.

In operation 740, the automatically generated constituent value mayinclude initiating a timer after the first series of successivecompressions has stopped. Here, operation 750 may include determining ifthe timer has reached a first time interval. Alternatively, operation750 may include determining if a data measurement corresponding to thefirst parameter has been completed.

In other embodiments, operation 740 includes rendering a digital valuefor the static value that has been decoded from the first sensor signal.Here, operation 750 may include determining when the constituent valueis first generated, or determining if a computation from the constituentvalue has been completed

Operation 750 may alternately include determining automatically from thefirst sensor signal that continuing compressions is merited.

The delivery of the first series of compressions in operation 710 mayinclude ventilation pauses for the patient to receive the ventilations,where the first series of compressions is stopped in operation 720 atthe beginning of one of the ventilation pauses.

FIG. 8 is another flowchart for illustrating methods for aCardio-Pulmonary Resuscitation (“CPR”) compression machine having amechanism for delivering successive compressions to a chest of a patientaccording to embodiments. Although this flowchart illustrates a varietyof operations in a particular order, these operations may be carried outin different orders to achieve similar results in other methodembodiments. The method shown in this illustrated flow chart may also bepracticed, for example, by the CPR chest compression machine 400 shownin FIG. 4.

According to an operation 805, a dynamic value of a second parameterabout the patient is detected. According to operation 810, a mechanismis controlled to deliver a next series of successive chest compressionsto a patient. The dynamic value of the second parameter in operation 805is detected while the patient is receiving chest compressions inoperation 810. Here, the dynamic value may be received automaticallyfrom a second sensor, or may be received via an interface by a humanrescuer.

According to another operation 815, it is determined whether the dynamicvalue of the second parameter indicates that the series of chestcompressions should be stopped at a first time. If it is indicated thatthe compressions should be stopped in operation 815, the mechanism iscontrolled to end delivery of the series of successive compressions inoperation 817. Operation 815 may include determining if the dynamicvalue exceeds a threshold. As mentioned above, various differentparameters and thresholds may be used to determine if the compressionsshould be stopped. For example, the second parameter may include manydifferent types of data, such as one or more of the following exampleparameters: 1) Arterial systolic blood pressure, where the threshold maybe, for example, about 80 millimeters of mercury; 2) Blood oxygensaturation, where the threshold may be, for example, about 90 percent;3) End tidal carbon dioxide, where the threshold may be, for example,about 30 millimeters of mercury; 4) Blood velocity, where the thresholdmay be, for example, zero ml/s; and/or 5) A patient's ECG, where thethreshold may be an ECG threshold criterion that is met. Examples of ECGthreshold criteria are given above.

The method may also include an optional operation 816 where it isdetermined if another stopping criterion is met. Here, if anotherstopping criterion is met, the mechanism is controlled to end deliveryof the series of successive compressions in operation 817. In someembodiments, the stopping criterion may be based on previously measuredstatic value, or a combination of the static and dynamic values.

After the compressions are stopped in operation 817, it is determinedwhether a static value of a patient parameter is to be detected inoperation 825. If it is determined that a static value does not need tobe detected (e.g., patient recovery is indicated from the detecteddynamic parameter in operation 815), an alert message may be outputtedin operation 870 to notify a rescuer that the patient may have regainedROSC or that a threshold for the dynamic parameter has been exceeded. Insome embodiments, operation 870 may follow directly operation 817.

If it is determined in operation 825 that a static value of a patientparameter is to be measured, the static parameter about the patient ismeasured in operation 830, and a signal indicating the static parametervalue is outputted. Operation 830 may also be reached if the mechanismis controlled to end the series of successive compressions in optionaloperation 820 without a stopping indication due to the dynamic parameteror another stopping criterion. The successive compressions may be endedat a second time in operation 830 that is determined from a previouslymeasured static value.

If the static value of the patient parameter is measured, a constituentvalue is generated in operation 840. In operation 850, it is thendetermined if a restart condition has been met based on the constituentvalue. The operation 850 may include determining if the static valueexceeds a threshold. As discussed above, this operation may include oneor more of the following: 1) Determining if an arterial systolic bloodpressure of the patient is above about 80 millimeters of mercury; 2)Determining if a blood oxygen saturation of the patient is above about90 percent; 3) Determining if an end tidal carbon dioxide of the patientis above about 30 millimeters of mercury; 4) Determining if a bloodvelocity of the patient is above zero ml/s; and/or 5) Determining if apatient's ECG includes an aspect of measured QRS complexes.

If a restart condition is not met in operation 850, an alert message maybe outputted in operation 870. Additionally, if the static parameterexceeds a threshold, an alert message may be outputted in operation 870.If a restart condition is met in operation 850, another series ofsuccessive compressions may be initiated in operation 810, and some orall of the operations described above may be repeated.

In this description, numerous details have been set forth in order toprovide a thorough understanding. In other instances, well-knownfeatures have not been described in detail in order to not obscureunnecessarily the description.

A person skilled in the art will be able to practice the presentinvention in view of this description, which is to be taken as a whole.The specific embodiments as disclosed and illustrated herein are not tobe considered in a limiting sense. Indeed, it should be readily apparentto those skilled in the art that what is described herein may bemodified in numerous ways. Such ways can include equivalents to what isdescribed herein. In addition, the invention may be practiced incombination with other systems.

The following claims define certain combinations and subcombinations ofelements, features, steps, and/or functions, which are regarded as noveland non-obvious. Additional claims for other combinations andsubcombinations may be presented in this or a related document.

What is claimed is:
 1. A system for performing Cardio-PulmonaryResuscitation (“CPR”) chest compressions on a patient, the systemcomprising: a CPR compression machine, including: a compressionstructure configured to deliver successive compressions to a chest ofthe patient; a first sensor adapted to detect a first parameter aboutthe patient and output a first sensor signal indicative of a dynamicvalue of the first parameter; and a processor configured to performoperations including: controlling the compression structure to deliver afirst series of successive compressions, determining from the dynamicvalue whether a stoppage criteria is met, after the stoppage criteria ismet, controlling the compression structure to stop delivering the firstseries of successive compressions to detect a static value of the firstparameter by the first sensor while the patient is not receiving chestcompressions, determining from a constituent value whether a restartcondition is met, and controlling the compression structure to startdelivering a second series of successive compressions when the restartcondition is met; and a ventilation machine coupled to the CPRcompression machine configured to ventilate the patient.
 2. The systemof claim 1, in which the restart condition is met also when a datameasurement corresponding to the static value has been completed.
 3. Thesystem of claim 1, in which the processor is coupled to receive thefirst sensor signal, the constituent value is a digital rendering of thestatic value that has been decoded from the first sensor signal, and therestart condition determination is performed when the constituent valueis generated.
 4. The system of claim 1, in which the processor iscoupled to receive the first sensor signal, the constituent value is adigital rendering of the static value that has been decoded from thefirst sensor signal, and the restart condition determination isperformed when a computation from the constituent value is indicated ashaving been completed.
 5. The system of claim 1, in which the restartcondition is met when a determination has been made automatically fromthe static value to perform compressions.
 6. The system of claim 1, inwhich the restart condition determination comprises a comparison of thestatic value and the dynamic value.
 7. The system of claim 1, in whichthe stoppage criteria includes stopping the first series of compressionsfor ventilation from the ventilation machine.
 8. The system of claim 1,the CPR compression machine further comprising a user interface adaptedto output an alert message to a user when the restart condition is notmet.
 9. The system of claim 1, in which the processor causes an alertmessage to be communicated to a device other than the machine when therestart condition is not met.
 10. The system of claim 1, in which theprocessor is further adapted to: determine whether a stopping criterionis met, then control the compression structure to stop delivering thesecond series of successive compressions when the stopping criterion ismet for the first parameter to be detected again by the first sensorwhile the patient is not receiving chest compressions, and then controlthe compression structure to start delivering a third series ofsuccessive compressions.
 11. The system of claim 10, in which thestopping criterion determination is made from the static value.
 12. Thesystem of claim 10, in which the second series is stopped at a secondtime determined from the static value.
 13. The system of claim 10, inwhich the stopping criterion is met when the detected static valueexceeds a threshold.
 14. The system of claim 13, in which the firstparameter includes arterial systolic blood pressure, and the thresholdis about 80 millimeters of mercury.
 15. The system of claim 13, in whichthe first parameter includes blood oxygen saturation, and the thresholdis about 90 percent.
 16. The system of claim 13, in which the firstparameter includes end tidal carbon dioxide, and the threshold about 30millimeters of mercury.
 17. The system of claim 13, in which the firstparameter includes to blood velocity, and the threshold is zero ml/s.18. The system of claim 13, in which the first parameter includes apatient's ECG, and the threshold is an aspect of measured QRS complexes.19. The system of claim 13, in which the CPR compression machine furthercomprises a user interface adapted to output an alert message to a userwhen the first parameter exceeds the threshold.
 20. The system of claim1, in which the CPR compression machine further comprises a secondsensor adapted to detect a dynamic value of a second parameter differentfrom the first parameter, the dynamic value detected about the patientwhile the patient is receiving the first series of chest compressions,and the first series of chest compressions is stopped at a first timedetermined from the dynamic value.
 21. The system of claim 20, in whichthe dynamic value is received automatically from the second sensor. 22.The system of claim 20, in which the dynamic value is entered via aninterface by a human rescuer.
 23. The system of claim 20, in which themachine stops the second series when the dynamic value exceeds athreshold.
 24. The system of claim 23, in which the second parameterincludes arterial systolic blood pressure, and the threshold is about 80millimeters of mercury.
 25. The system of claim 23, in which the secondparameter includes blood oxygen saturation, and the threshold is about90 percent.
 26. The system of claim 23, in which the second parameterincludes end tidal carbon dioxide, and the threshold about 30millimeters of mercury.
 27. The system of claim 23, in which the secondparameter includes to blood velocity, and the threshold is zero ml/s.28. The system of claim 23, in which the second parameter includes apatient's ECG, and the threshold is an included aspect of measured QRScomplexes.
 29. The system of claim 23, further comprising: a userinterface adapted to output an alert message to a user when the dynamicvalue exceeds the threshold.
 30. The system of claim 1, furthercomprising generation means for automatically generating the constituentvalue.
 31. The system of claim 1, the processor further configured tocontrol the compression structure to deliver the second series ofsuccessive compressions for a length of time based on the firstparameter.
 32. A method for a Cardio-Pulmonary Resuscitation (“CPR”)compression machine having a mechanism configured to deliver successivecompressions to a chest of a patient, the method comprising: controllingthe mechanism to deliver a first series of successive compressions tothe chest of the patient; detecting a first parameter about the patientand outputting a first sensor signal indicative of a dynamic value ofthe first parameter, determining from the dynamic value whether stoppagecriteria is met, after the stoppage criteria is met, controlling themechanism to end delivery of the first series of successive compressionsand detecting a static value of the first parameter while the patient isnot receiving chest compressions, and outputting a second sensor signalindicative of the static value of the first parameter; automaticallygenerating a constituent value; determining from the constituent valuewhether a restart condition has been met; controlling the mechanism todeliver a second series of successive compressions when the restartcondition is met; and ventilating the patient after the stoppagecriteria is met and prior to the restart condition being met.
 33. Anarticle comprising a storage medium having instructions stored thereonthat when executed by at least one device result in: controlling amechanism to deliver a first series of successive compressions to achest of a patient; detecting a first parameter about the patient andoutputting a first sensor signal indicative of a dynamic value of thefirst parameter; determining from the dynamic value whether stoppagecriteria is met; after the stoppage criteria is met, controlling themechanism to end delivery of the first series of successive compressionsand detecting a static value of the first parameter while the patient isnot receiving chest compressions, and outputting a second sensor signalindicative of the static value of the first parameter; automaticallygenerating a constituent value; determining from the constituent valuewhether a restart condition has been met; controlling the mechanism todeliver a second series of successive compressions when the restartcondition is met, and ventilating the patient after the stoppagecriteria is met and prior to the restart condition being met.